Re: Very slow graphics rendering
- To: mathgroup at smc.vnet.net
- Subject: [mg14156] Re: Very slow graphics rendering
- From: migdie at encomix.es (Miguel)
- Date: Mon, 28 Sep 1998 18:57:21 -0400
- References: <6unfa9$o75@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi Julio,
I saw in the Mathematica book this paragraph, which is about
ParametricPlot3D:
You should realize that when you draw surfaces with ParametricPlot3D,
the exact choice of parametrization is often crucial. You should be
careful, for example, to avoid parametrizations in which all or part of
your surface is covered more than once. Such multiple coverings often
lead to discontinuities in the mesh drawn on the surface, and may make
ParametricPlot3D take much longer to render the surface.
Hope this help,
Miguel
On 28 Sep 1998 03:53:45 -0400, "julio vera" <lvera at varela.reu.edu.uy>
wrote:
>Hello.
>Thanks to Sergio Terrazas and Will Self for the very useful answers I
>received to my previous question.
> With their help, I could make a graphic of part of a 3D object, like
>this piece of a sphere:
>ParametricPlot3D
>[{x , y , If[ x^2 + y^2 < (4/5)^2 , Sqrt [ 1 - x^2 - y^2 ] ] } , {x , -1
>, 1 , 1/75} , { y, -1 , 1 , 1/75} ]
>With an increment bigger than 1/75, the limits of the plot are quite
>irregular.
>My question is if I can achieve a definite curve limit for a partial 3D
>object in a more efficient way, since for each graphic I have to wait
>more than an hour. I work with 16 mega RAM and a 686 Cyrix motherboard.
>Another aspect: the graphics get rather dark, because of the amount of
>lines that are drawn. After the picture is finished, I can eliminate
>the black in them by using preferences on the graphic object, with the
>right button of the mouse.
>Maybe these 2 problems are related, since the delay may be happening
>because of all the division lines that are drawn.
>Thanks in advance,
>Julio Vera